Benzyl phenyl ether (BPE) was reacted to discuss the yields of decomposed products using solvents having various values of carbon aromaticities (fa) prepared from 2-rings compounds (decalin, tetralin and naphthalene) and a synthetic pyrite as catalyst. The reactions were carried out in a 50 ml autoclave at 673 K to 743 K of the reaction temperature under 3 Mpa of initial hydrogen or nitrogen pressure for 30 min.The conversions in all reactions were 100 wt% based on BPE. In the reaction using decalin as solvent, the decomposed products consisted of toluene, phenol and benzene were the most abundant constituent, In the reaction using tetralin or naphthalene as solvent, the decomposed products yield decreased because that benzyl radical produced from BPE by thermal cracking reacts with solvent to produce benzyltetralin or benzylnaphthalene. In the feactions using solvents having equal fa-value prepared by mixing decalin and tetralin, or decalin and naphthalene, the decomposed products yields were not so much different. However the decomposed product yields in the reaction using the mixed solvent of decalin and naphthalene was somewhat higher than that using the mixed solvent of decalin and tetralin.It is suggested that in the reaction using a mixed solvent having particular fa value, the decomposed product yields would increase.In future work the variations of solvents before and after reaction should be studied in detail to clarify hydrogen transfer from solvent to products.